Continuous spell checking is enabled in the inspector, but does not really make sense for JavaScript code,CSS property values and HTML attribute names. It should be disabled. I tried using spellcheck="false" but it didn’t work because I think this attribute is not checked everywhere it should be checked in the editing code.
I also tried calling -[WebView setContinuousSpellCheckingEnabled:NO] in WebInspectorClient, but that sets the user default and thus affects all future WebViews in the app.
Created attachment 32673 [details] Use the spellcheck attribute to disable continuous spell checking in the inspector
Fixed in <http://trac.webkit.org/changeset/45835>.